1. Field of the Invention
This invention relates to radio communications networks. More particularly, this invention relates to planning and management of dynamic communications networks based upon propagation forecasting, modeling techniques and the ability to adapt the network according to continually updated propagation and traffic forecasting.
2. Description of the Prior Art
A major problem in the field of radio communications is caused by the environment and its effects on network performance, making these elements significant network planning factors. Meteorological phenomena that affect the propagation reliability of communications links include, depending on the radio frequency of the link, atmospheric refraction, layering (ducting), rain, absorption and fog. Examples of environmental phenomena effecting communications reliability include fading caused by clear-air atmospheric layering on microwave links, rain attenuation on millimeter wave links and attenuation by fog of optical links. These changeable environmental factors have a profound impact on the dynamic networks used by the U.S. Army for tactical communications.
Independent of such harsh environmental factors, both the configuration and geographical location of these networks can change on a daily or even hourly basis. Combining the harsh environmental effects of phenomena such as fading, rain attenuation and attenuation by fog with the changeable configuration and geographical location of the U.S. Army's tactical communications networks can seriously degrade anticipated network performance. A stationary communications network for long-term use can be readily designed based on typical, historical local weather patterns and their effect on propagation, however, a moveable communications network operating in different climates must be tailored to local conditions that exist at the time of use.
Traditional propagation reliability methods are based on long-term historical meteorological statistics. While propagation forecasting has undergone improvement in recent years, communications network planning and management today is not based upon the known weather forecast and its probable effect on radio propagation. See for example, A Regression Model for Forecasting Microwave Radio Fading at Palmetto, Georgia, J. A. Schiavone and S. H. Hermiller, IEEE Transactions on Antennas and Propagation, Vol. AP-34, No. 7, pp. 936-942, July 1986.
There have been advances in terms of propagation and reliability modeling during fading using historical statistics resulting in a propagation reliability model for tactical line-of-sight radio which has been developed for a large range of climates, terrains, fade margins and path lengths. See, for example, Line-of-Sight Radio Fading Prompts Remedial Program, K. H. Brockel and A. Vigants, SIGNAL Magazine, November 1992. While the effects of weather on propagation are well known, up to now there have been no practical solutions for quickly calculating the propagation effects from predicted short-term weather conditions and then rapidly adjusting the network plan or components of a communications system to meet given network performance parameters.
Up to now, the effects of weather and communications-traffic patterns on the communications quality of dynamic networks are typically either anticipated based upon historical data, or compensated for by man-calculated adjustments to networks in the field. Current tactical network management systems, based on traditional traffic engineering using long-term traffic performance statistics or rules of thumb, do not provide a facility for automatically planning and engineering communications networks based on current traffic forecasts and the real-time analysis of current traffic loads. Tactical networks cannot be planned in this manner because they are continually dynamic. In a tactical environment, a battlefield commander needs to design a communications network based on tonight's or tomorrow night's weather if that is the scheduled time of the military operation. Those concerned with the planning and management of communications networks in either a tactical or commercial environment have long recognized a need for an automated method to plan a communications system based on anticipated weather, propagation patterns and network traffic, monitor and calculate the impact of such environmental changes on the network quickly and then adjust the communications network for optimized performance based upon these environmental changes.
This invention fulfills that long-recognized need by providing an automated method of network planning and management which will automatically plan, engineer and direct the installation and continuing operation of a radio communications network based upon planning tools integrating the effects of forecast weather, environmental feedback, real-time network status and necessary traffic dimensions, a dynamic network model and automatic experience-based improvements of algorithms used in the dynamic network model. An automated communications network planner is also provided.
The present invention addresses the practical needs of the tactical network planner and manager by using near-future propagation forecasts for network planning and real-time propagation information for network management, with an emphasis on 24-hour forecasting because many meteorological phenomena have a diurnal (24-hour) cycle. By utilizing updated weather, performance and traffic data received from the network, with the aid of artificial intelligence (AI) techniques, necessary environment-driven changes can be made continuously and on a real-time basis operating on large masses of data which only a computer can effectively handle. Further, this invention utilizes tools such as computer models, algorithms, computer simulations and AI-based tools in a new way along with currently available tactical system/network management technology.
While this invention may be readily used in tactical military communications systems, there are numerous commercial applications in areas such as mobile or cellular telephones, as well as any communications system that can be incapacitated by adverse propagation conditions. A key aspect of the method and apparatus of this invention is the ability to use and automatically update propagation, weather and traffic algorithms so that the communications system can automatically send reconfiguration "change orders" to the network to compensate for the harmful effects of these phenomena.
Examples of propagation forecasting tools may be found in the following references:
"24-Hour Network Performance Management System Technical Paper," Jan. 21, 1993, U.S. Army CECOM Space and Terrestrial Communications Directorate Line-of-Sight Propagation Reliability Working Group; PA0 Michael J. Harrigan, Kenneth H. Brockel, William P. Sudnikovich, Arvids Vigants, William T. Barnett, Stanley Conway-Clough, Richard Wood, Robert Edwards, Joli Toth and Julius Sunshine "24-Hour Network Performance Management System," MILCOM 94 Conference Technical Paper, Fort Monmouth, N.J., Oct. 2-5, 1994; PA0 "Rain Propagation Reliability Forecasting Method Technical Memorandum," May 17, 1993, U.S. Army CECOM Space and Terrestrial Communications Directorate Line-of-Sight Propagation Reliability Working Group; and PA0 Network Management Tool Detailed Operational Concepts Document, Jan. 5, 1994. U.S. Army CECOM Space and Terrestrial Communications Directorate Network Management Automation & Integration Working Group. Further, an example of a propagation reliability model may also be found in U.S. Pat. No. 5,669,063, entitled "Method of Establishing Line of Sight Propagation," which was issued as on Sep. 16, 1997, which is hereby incorporated by reference, in which Messrs. Brockel and Sudnikovich are also co-inventors of this invention. PA0 Eric C. Ericson, Lisa Traeger Ericson, and Daniel Minoli, "Expert Systems Applications in Integrated Network Management," Artech House, Inc., 1989; PA0 "MIL-STD-2045-38000, Network Management for DOD Communications (Draft)," January 4, 1993; PA0 V. J. Procopio, Kenneth H. Brockel, Joseph R. Inserra, Francis G. Loso, Paul A. Major, Kenneth D. Chaney, Robert J. Locher, Arvids Vigants, Mark Riehl and William T. Barnett, "Tactical Line-of-Sight Radio Propagation Reliability Modeling," MILCOM 93 Conference Technical Paper, Boston, Mass., Oct. 11-14, 1993; and PA0 K. H. Brockel, Tommy Cheng and MAJ Michael Mitchum, "NPT--A Success Story Evolving From Teamwork and Innovation," MILCOM 93 Conference Technical Paper, Boston, Mass., Oct. 11-14, 1993.
Examples of systems or devices which manage communications networks may be found in the following references: